My boyfriend’s first dog was able to be free fed and never overate. When he got a puppy, it would eat whatever it could find and ballooned up. The vet said if he just kept refilling the bowl, the dog would adapt to the fact that it would get enough to eat and learn to pace herself. Nope! She would eat, go vomit, then come back to eat more. Her brain is just wired different, so she’s on a very strict diet.